627
FXUS65 KBYZ 221537
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
937 AM MDT MON JUN 22 2026
KEY MESSAGES
- ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TODAY. A FEW
THUNDERSTORMS MAY BECOME STRONG TO SEVERE MAINLY EAST OF
BILLINGS. MAIN THREATS ARE HAIL, STRONG WINDS, AND HEAVY RAIN.
- MAINLY DRY AND TRENDING WARMER TUESDAY AND WEDNESDAY.
- DAILY CHANCE OF PRECIPITATION THURSDAY INTO THE WEEKEND.
- A STRONG WEATHER SYSTEM MAY (MODERATE CHANCE) BRING MORE
WIDESPREAD PRECIPITATION AND MOUNTAIN SNOW TO THE AREA OVER THE
WEEKEND. STAY UP TO DATE WITH THE LATEST FORECAST.
UPDATE
UPDATED FORECAST FOR THE LATEST MODEL TRENDS ON PRECIPITATION AND
THUNDERSTORM POTENTIAL. CURRENT RADAR IS SHOWING A LONE OF
DEVELOPING THUNDERSTORMS FROM EASTERN MUSSELSHELL COUNTY SOUTHWEST
TO JUST EAST OF BILLINGS. THIS IS ALONG THE WEAK COLD FRONT THAT
WILL SLOWLY PUSH SOUTHEAST THROUGH THE FORECAST AREA THROUGH THE
DAY TODAY. THIS LINE WILL BE THE MAIN FOCUS FOR SEVERE
THUNDERSTORM DEVELOPMENT TODAY INTO EARLY THIS EVENING AS IT
SLIDES SOUTHEASTWARD. DRIER NORTHERLY WINDS WILL FILL IN BEHIND
THE FRONT. UPSLOPE FROM THESE WINDS ALONG WITH RESIDUAL MOISTURE
FROM WEEKEND CONVECTION WILL KEEP A GOOD CHANCE FOR SHOWERS AND
THUNDERSTORMS GOING BEHIND THE FRONT THROUGH EARLY EVENING,
HOWEVER THE POTENTIAL FOR STRONG STORMS WILL BE GREATLY DIMINISHED
THE FURTHER BEHIND THE FRONT YOU GET.
AHEAD OF THE FRONT STORMS WILL GET GOING LATE THIS MORNING AND
CONTINUE INTO THE EARLY EVENING HOURS. SPC PUSHED THE SLIGHT RISK
FURTHER NORTH INTO THE SOUTHERN PORTION OF SE MONTANA AND ACROSS
SHERIDAN COUNTY. THE MAIN THREAT WITH STORMS WILL BE LARGE HAIL
AND LOCALLY HEAVY RAINFALL. AN 80-90KT JET STREAM CROSSING THE
AREA WILL KEEP STORMS MOVING SO THE THREAT OF FLASH FLOODING,
WHILE NOT COMPLETELY GONE, IS DIMINISHED AS LATENCY TIME WILL BE
REDUCED. THAT SAID A QUICK HALF TO ONE INCH OF PRECIPITATION IS
POSSIBLE WITH THE STRONGER CONVECTION TODAY AND WILL NEED TO KEEP
AN EYE ON AREA BURN SCARS THAT CAN FLOOD AT MUCH LOWER
PRECIPITATION AMOUNTS.
MAIN TAKEAWAYS, EXPECT SHOWERS AND THUNDERSTORMS TODAY AND SOME
MAY BE SEVERE MAINLY EAST OF BILLINGS. LARGE HAIL AND LOCALLY
HEAVY RAINFALL IS POSSIBLE WITH THE STRONGER STORMS SO HAVE A PLAN
TO GET TO SHELTER IF STORMS APPROACH YOUR LOCATION. STORMS WILL
START OFF EARLIER THAN USUAL TODAY, AROUND NOON-TIME. CHAMBERS
DISCUSSION
TODAY THROUGH SUNDAY...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE FORECAST THIS
MORNING AHEAD OF AN APPROACHING COLD FRONT. WHILE INSTABILITY
LOOKS TO BE ENOUGH TO SUPPORT A HEAVIER SHOWER OR THUNDERSTORM AT
TIMES, THE CHANCE OF SEEING A SEVERE THUNDERSTORM EARLY THIS
MORNING IS VERY LOW. THIS CHANGES LATE THIS MORNING INTO THIS
AFTERNOON AND EVENING WHEN ADDITIONAL SHOWERS AND THUNDERSTORMS
ARE FORECAST TO DEVELOP AS A COLD FRONT MOVES THROUGH THE AREA.
WITH THIS, MODEST INSTABILITY (CAPE VALUES AROUND 250 TO 1250
J/KG), GOOD SHEAR (35 TO 45 KNOTS) DUE TO AN APPROACHING JET
STREAK, AND ELEVATED PRECIPITABLE WATER VALUES (0.75 TO 1.00 INCH)
WILL SUPPORT THE POTENTIAL FOR A FEW STRONG TO SEVERE
THUNDERSTORMS. AT THIS TIME, THE STORM PREDICTION CENTER HAS A
MARGINAL RISK (1/5) OF SEVERE THUNDERSTORMS OVER SOUTH- EASTERN
MONTANA AND NORTH- CENTRAL WYOMING AND A SLIGHT RISK (2/5) OF
SEVERE THUNDERSTORMS OVER NORTH-EASTERN WYOMING LATE THIS MORNING
INTO THE EVENING. THE MAIN THREATS WITH ANY STRONG TO SEVERE
THUNDERSTORM THAT DEVELOPS ARE HAIL UP TO HALF DOLLAR SIZE (1.25
INCHES), STRONG WIND GUSTS OF 60+ MPH, AND HEAVY RAIN. THE ONE
WRINKLE IN THIS SEVERE THUNDERSTORM POTENTIAL IS THE MORNING
CONVECTION AND ASSOCIATED CLOUD COVER OVER EASTERN MONTANA, WHICH
MAY STABILIZE THE ATMOSPHERE AND LIMIT THE STRENGTH AND EXTENT OF
THUNDERSTORMS LATER IN THE DAY. ON THAT NOTE, THIS CONVECTION AND
CLOUD COVER MAY CLEAR OVER SOUTH-CENTRAL MONTANA EARLIER IN THE
DAY, SO WHILE THIS AREA IS AT A LOWER RISK OF SEVERE WEATHER, IT
IS AN AREA TO WATCH SHOULD BETTER DIURNAL HEATING DEVELOP.
CURRENTLY, A FEW OF THE CONVECTIVE ALLOWING MODELS (CAMS) DO SHOW
A STRONG TO SEVERE THUNDERSTORM DEVELOPING THAT FAR WEST, SO IT IS
SOMETHING TO WATCH.
TUESDAY WILL BE A DRIER DAY AS CYCLONIC FLOW IS REPLACED BY AN
APPROACHING LOW AMPLITUDE RIDGE. WITH THAT SAID, THERE MAY BE
ENOUGH ELEVATED INSTABILITY IN THE CYCLONIC FLOW TO SUPPORT A
LIGHT SHOWERS MAINLY NEAR THE MOUNTAINS AND FOOTHILLS (10 TO 25
PERCENT CHANCE). WEDNESDAY WILL BE ANOTHER MOSTLY DRY DAY, THOUGH
A SUBTLE WAVE AHEAD OF THE LOW AMPLITUDE RIDGE MAY BRING LIGHT
SHOWERS TO THE AREA DURING THE DAY (10 TO 50 PERCENT CHANCE,
GREATEST OVER THE MOUNTAINS).
THE WEATHER PATTERN LOOKS TO BECOME MORE ACTIVE THURSDAY AS A
MORE ROBUST SHORTWAVE MOVES THROUGH THE REGION. WHILE SOME
UNCERTAINTY IN THE DEPTH OF THIS WAVE EXISTS BETWEEN MODELS, THERE
LOOKS TO BE ENOUGH INSTABILITY AND LIFT TO FAVOR AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS (MODERATE CHANCE). DEPENDING ON
THE DEPTH OF THE WAVE, A FEW STRONG TO SEVERE THUNDERSTORMS COULD
ALSO DEVELOP (LOW CHANCE).
FRIDAY INTO THE WEEKEND, A LARGE WEATHER SYSTEM IS EXPECTED TO
MOVE INTO THE NORTHWESTERN UNITED STATES IN SOME FASHION. WHILE
QUITE A BIT OF UNCERTAINTY REMAINS IN THE TRACK OF THIS WEATHER
SYSTEM, ENSEMBLE FORECASTS SUGGEST PRECIPITATION, COOLER
TEMPERATURES, AND WINDY CONDITIONS WILL IMPACT PORTIONS OF THE
NORTHWESTERN UNITED STATES DURING THIS TIME. AS FOR OUR AREA,
SHOWERS AND THUNDERSTORMS ON THE LEADING EDGE OF THE WEATHER
SYSTEM ARE CURRENTLY FORECAST ON FRIDAY. DEPENDING ON WHERE THE
CORE OF THE LOW PRESSURE SYSTEM GOES SATURDAY INTO SUNDAY, OUR
AREA COULD SEE MORE WIDESPREAD PRECIPITATION FOR THE WEEKEND, OR
DRIER AND MORE WINDY CONDITIONS. IN ADDITION, THIS WEATHER SYSTEM
MAY HAVE ENOUGH COLD AIR ASSOCIATED WITH IT TO SUPPORT SNOW OVER
THE HIGHER ELEVATIONS OF THE MOUNTAINS (MODERATE CHANCE). IF YOU
HAVE OUTDOOR OR TRAVEL PLANS LATE THIS WEEK INTO THE WEEKEND,
ESPECIALLY IN THE MOUNTAINS, MAKE SURE TO STAY UP TO DATE WITH THE
LATEST FORECAST. LA
AVIATION
AN AREA OF SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
MOVE EAST THIS MORNING. BRIEF MVFR CONDITIONS ARE POSSIBLE UNDER
THUNDERSTORMS. MVFR CEILINGS WILL MOVE INTO NORTHWEST AREAS AFTER
DURING THE MORNING HOURS AND MAY AFFECT KBIL, LIFTING INTO THE
AFTERNOON. LOOK FOR SHOWERS AND THUNDERSTORMS TO INCREASE IN
COVERAGE HEADING INTO THE AFTERNOON, WITH A FEW STRONG TO SEVERE
THUNDERSTORMS POSSIBLE FOR AREAS GENERALLY EAST OF KBIL, LASTING
THROUGH THE EARLY EVENING. THE MAIN THREAT WITH THESE STORMS WILL
BE LARGE HAIL, STRONG WINDS TO 50 KTS AND HEAVY RAIN. MVFR TO IFR
CONDITIONS ARE POSSIBLE WITH THE THUNDERSTORMS THIS AFTERNOON AND
EVENING. STP
PRELIMINARY POINT TEMP/POPS
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 072 049/075 053/076 053/081 055/089 060/077 051/069
4/T 40/U 12/T 13/T 21/B 48/T 75/T
LVM 074 043/075 046/075 046/079 048/085 049/069 041/062
5/T 30/U 01/B 24/T 22/T 49/T 87/T
HDN 073 047/075 049/076 050/081 053/089 058/078 049/071
4/T 30/U 12/T 15/T 31/B 37/T 86/T
MLS 072 049/072 048/073 050/078 054/083 058/079 053/070
6/T 40/U 01/B 03/T 41/B 45/T 65/T
4BQ 073 050/071 048/072 050/076 054/083 059/080 053/070
6/T 60/B 02/W 26/T 51/B 36/T 86/T
BHK 073 046/070 043/071 045/075 050/078 054/079 050/070
5/T 60/N 01/B 01/B 41/N 46/T 76/T
SHR 073 046/069 045/072 046/076 049/086 054/077 046/068
5/T 62/T 34/T 37/T 32/T 27/T 77/T
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page